1. Field of the Invention
The invention is in the field of telecommunication network control.
2. Description of the Background Art
Toll-free long distance calling (e.g., using 800 and 888 numbers) has grown over the last 10 years, according to recent press reports, to comprise as much as 25% of all domestic interstate voice traffic. Much of this growth can be attributed to the expanding uses to which toll-free numbers are being put (e.g., for calling cards, nationwide paging, telemarketing campaigns, customer service centers, etc.). The called party, instead of the caller, typically pays the tolls associated with such calls to the telecommunication carrier whose network carried the call.
A party wishing to offer toll-free calling to callers today must sign up for toll-free service (typically, using 800 or 888 prefixes) with an established interexchange carrier. This carrier is designated as the called party's presubscribed interexchange carrier for all calls made to the designated toll-free number. Regulatory authorities now permit the called party offering toll-free calling (the "800 Customer") to change its carrier without changing its toll-free number.
When a caller in the United States, for example, dials 800-NXX-XXXX or 888-NXX-XXX, the local exchange carrier's central office switch associated with that caller recognizes that the number dialed is a toll-free number. The switch sends a query to a remote centrally-administered database (e.g., the 800 Database) to determine which interexchange carrier is the designated carrier for calls to this toll-free number. The 800 Database responds to the switch by providing a carrier identifier for the designated interexchange carrier (e.g., the carrier with whom the 800 Customer has an account relationship). The switch then routes the call to that carrier for completion. The interexchange carrier translates the dialed toll-free number into the specific NPA-NXX-XXXX destination associated with that toll-free number in a database maintained by the carrier. The carrier then completes the call to the destination specified. All calls to this toll-free number will be carried by this designated carrier unless and until the 800 Customer decides to change carriers. In that event the newly selected interexchange carrier will notify the administrator or other party maintaining the 800 Database and the 800 Database will be updated to reflect this change.
Large 800 Customers (e.g., airline reservation centers, inbound telemarketing companies, etc.) generally install dedicated access facilities to and from one or more interexchange carriers' points-of-presence, primarily to avoid the access charges levied by the local exchange carrier if calls are received via the public switched telephone network. Inbound toll-free calls are routed in that case from the interexchange carrier's point-of-presence directly to the 800 Customer's premises, without passing through the local exchange carrier's local switching network. If, however, the dedicated access facility has a "trouble" or is otherwise not available, the interexchange carrier will normally route all calls from its point-of-presence to the local exchange carrier's local switched network for completion to the 800 Customer's premises (in that case, of course, the 800 Customer will likely pay the local exchange carrier's access charges for all such calls).
Typically, 800 Customers pay the interexchange carrier for each completed call, based most often on the duration of the call. Carriers usually offer better pricing to those 800 Customers who sign fixed-price contracts with significant volume commitments and terms of at least 12 months.
Many locally managed telecommunication switching systems, such as PBXs, employ "least cost routing" software to reduce telecommunication costs. The system's manager arranges with more than one interexchange carrier to carry the system's traffic. The manager keeps track of each carrier's charges and populates the routing table in the "least cost routing" software. The charges may be the regularly tariffed charges of the subscriber's primary carrier or contracted charges offered by an alternate carrier for a bulk discount or for discounting traffic during a specific time period during the day. The "least cost routing" software will examine each call attempt and automatically decide which carrier is the best economic choice for that call.
In the last few years a great deal of competition has developed among telecommunication carriers to win new 800 Customers. As telecommunication service becomes more of a commodity, increased competition would be of great benefit to 800 Customers, large and small.